Gallery of Legends (acorn) Artifact Attraction Visit Exile cards from the top of your library until you exile a nonland card, then choose a legendary creature card name with the same mana value as that card
Commander players love abilities that trigger upon entering the battlefield, like Quantum RiddlerQuantum Riddler, Gray Merchant of AsphodelGray Merchant of Asphodel and Imperial RecruiterImperial Recruiter
Im a big fan of cycling abilities with bonus effects attached, and Rampaging War Mammoth is a good one
I will say that prices on some versions of Ancient Tomb have dipped since it was reprinted in the Lord of the Rings set, so if you do want one, now might be a good time to grab it
The Hareruya 2 branding seems to be an effort to separate it from the original MTG shops and focus on Pocket Monsters
However, try to use the Poison half of the Grass line, such as the Weedle, Nidoran, and Koffing series